Lubricating apparatus



Oct. 10, 1939. E. w. DAVIS LUBRICATING APPARATUS A Filed Nov. ll, 1935Patented Oct. 10, 1939 UNITED STATES PATENT OFFIQE LUBRICATING APPARATUSporation of Virginia Application November 11, 1935, Serial No. 49,174

2 Claims.

My invention relates generally to lubricating apparatus, and moreparticularly to oil cups adapted to be more or less permanently securedto the bearing to be lubricated, and constructed and arrangedautomatically to feed oil to the bearing.

Oil cups have been devised in which the oil is fed from a reservoir intoa well containing air and forced from this well whenever the temperlature of the bearing or the surrounding atmosphere increases. Myinvention relates to improvements in this type of oil cup, moreparticularly in the provision of improved means for preventing rapiddraining of the reservoir of the l5 oil cup whenever the cap is removedfrom the reservoir during the operation of relling the latter.

It is thus an object of my invention to provide an improved oil cupconstruction in which means are provided to prevent rapid draining ofthe reservoir of the cup during the operation of lling the reservoir.

A further object is to provide an improved thermally controlled oil cupwhich is simple construction and may be economically manufactured.

Other objects will appear from the following description, referencebeing had to the accompanying drawing, in which 301 Fig. l is anelevation of my improved oil cup shown attached to a bearing to belubricated, the latter being shown in transverse section; and

Fig. 2 is an enlarged central vertical sectional View taken on the line2-2 of Fig. 1

The oil cup of my invention comprises a reser- Voir formed of a glasstube I0 which is clamped between a top I2 and bottom I4, suitablegaskets I6 and I8 being provided to seal the joints and to distributethe clamping pressure on the edges of the glass. A tube 20 is threadedon an upwardly extending boss 22 formed on the bottom I4y the upper endof the tube 2li being externally threaded to the top I2 so that the tubeforms a tie rod between the top I2 and the bottom I4.

The tube has a plurality of apertures 24 through which the interior ofthe tube 20 is in communication with the reservoir I. The upper end ofthe tube 20 is normally closed by a cap 26 threaded over the end of thetube and which presses against an annular gasket 28 located in asuitable recess formed in the upper surface of the top I2. An opening 30is provided in the tube 20 and is located so as to extend across thesealing surfaces of the gasket 28.

A Well 32 is threaded over an annular flange 34 formed integrally withthe bottom I4 and has an annular gasket 36 located in a groove in itsupper surface rThe gasket 36 forms an air-tight seal between the welland an annular ridge 38 projecting downwardly from the bottom I4 of the5 reservoir. The well 32 is provided with a threaded shank 40 which isadapted to be screwed into the oil hole of a bearing, the shank beingprovided with a cylindrical bore 42 which communicates with theatmosphere through a vent po-rt 44 and l0 which communicates with theinterior of the well S2 through an outlet port 46 of small diameter.

An outlet pipe 48 is secured in a boss 5B forming part of the bottom I4and has its upper end communicating with an annular channel 52 15 formedin the upper surface of the bottom I4, the channel being covered by a nemesh screen 54 which is held in place by the center tube 2D. rThe lowerend of the outlet pipe 43 is restricted by a plug 55 which has a helicalgroove 58 formed 20 upon its external surface. The plug 5S is preferablysecured in the lower end of the pipe 48 by a press t, although, ifdesired, it may be secured in place by other means.

An air escape tube 68 is secured in the boss 25 22 of the bottom I4 andat its upper end is restricted by a plug 62 which is similar to the plug56 and has a helical groove 64 formed thereon. The lower end of the airtube B0 is preferably cut 01T at an angle as indicated at 66. Theinternal 30 diameters of the outlet pipe 48 and of the air escape tube6U are so small that oil and air cannot simultaneously ow in oppositedirections through either of these passageways.

In use the oil cup is screwed into the oil hole 35 68 of a bearing "I0,as indicated in Fig, 1, and assuming the reservoir to be lled orpartially iilled with lubricant, the operation of the oil cup Will be asfollows:

Oil will feed from the reservoir through the 40 iiltering screen 54,pipe 48, through the helical groove 58 and into the air trap or Well 32until the level of the oil within the well 32 rises slightly above thelower end of the air tube 60. The outlet port 46 of the well 32 is ofsuch small diameter 45 that oil and air will not simultaneously flowtherethrough in o-pposite directionsl Since the reservoir and the wellare sealed against atmospheric pressure, only a very minute quantity ofoil will ilow from the opening 46 unless the tem- 50 perature of the airin the Well 32 is increased.

Whenever the bearing to which the oil cup is attached becomes slightlywarm due to insufficient lubrication, heat will be transmitted from thebearing to the well 32, causing the air within 55 the well to expand andforce oil from the well through the port 46 into the bearing. When thisoil reaches the bearing the latter will gradually cool and as a resultthe air within the well 32 will again contract and form a partial vacuumwithin the well. This partial vacuum will result in drawing air from theatmosphere through the vent port 44 and outlet port 46. Whenever thelevel of the oil within the Well 32 drops below the end of the air trappipe 60, some of the air will escape from the well 32 through the pipe66 and will flow slowly around the helical groove 64 of the plug 62 intothe tube 20 and thence through the apertures 24 into the reservoir l0,thus replacing the oil which is simultaneously owing therefrom throughthe pipe 48.

The air escape tube Ell will normally be iilled with air. The only timethat it will be filled with oil is immediately after lling, Air enteringthe well 32 through the outlet port 46 will bubble upwardly directlyinto the tube 65 and replace the oil contained therein within a shorttime after the lubricator has been filled. Since the hydrostatic headupon the oil in the helical passageway 56 is greater than that upon the011 in the upper end of the passageway 64, the oil will necessarily flowdownwardly through the pipe 48 and passageway 58 while the air will owupwardly through the air escape tube 66 and helical passageway 54. Itwill be understood that the air contained in the upper end of thereservoir I6 will, during normal operation of the device, be atsub-atmospheric pressure. The dii-ference between the pressure of theair in the upper end of the reservoir lll and that of the atmospherewill be substantially that represented by a column of oil extending fromthe outlet port 46 to the level of the oil in the reservoir l.

In oil cups of the above-described type which have been devised in thepast, difficulty was eX- perienced in that whenever the cap 26 wasremoved for the purpose of relling the reservoir l0, such oil whichremained in the reservoir would flow rather rapidly from the reservoirinto the well and through the outlet port 46 into the bearing, floodingthe latter and sometimes oW- ing also through the vent port 44 withresulting wastage of oil, and causing dripping of excess oil from thebearing. In some types of machinery the excess oil would soil and damagethe product of the machine on which the bearing is mounted.

With the provision of the restriction plugs 56 and 62, the flow of oilfrom the reservoir into the bearing is hindered whenever the lling cap26 is removed and the oil in the reservoir subjected to atmosphericpressure. If the restriction plugs 56 and 62 were not provided, all ofthe oil remaining in the reservoir would rapidly discharge through theoutlet port 46, but since the grooves 58 and 64 in these plugs are ofrelatively small crosssectional area, the passage of oil from thereservoir to the well is hindered so that during the time that thefilling cap 26 is removed only a very small excess quantity of lubricantwill flow to the bearing. 'Ihe grooves in the plugs 56 and 62 are ofsulicient size that they will not easily become clogged and aresufficiently long so as to oder appreciable resistance to the iiow ofoil. Under the low hydraulic head which is present, the resistance plugspermit only very slow ow of oil from the reservoir.

While I have illustrated and described a preferred embodiment of myinvention, many modifications may be made without departing from thespirit of the invention, and I do not wish to be limited to the precisedetails set forth but desire to avail myself of all changes within thescope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. In an oil cup, the combination of a reservoir, an air trapping wellassociated therewith, a pair of pipes communicating with said reservoirand depending inte said well, and restriction plugs in said pipes, saidplugs forming relatively long restricted permanently open passageways insaid pipes to prevent rapid flow of oil from said reservoir to saidwell.

2. In an oil cup, the combination of a reser- Voir, an air trapping wellassociated therewith, an oil conducting passageway, and an air ventpassageway, both of said passageways extending in a substantiallyVertical direction and connecting said reservoir with said well, saidair vent passageway having a restriction near its upper end and said oilconducting passageway having a restriction near its lower end, both ofsaid restrictions forming continuously open channels for the ilow offluid through said passageways.

ERNEST W. DAVIS.

